PLUS ONEAbout CHESS PLUS ONE
CHESS PLUS ONE is a passion project reimagining classic chess on an unusual 8-column by 9-row board — a normal chessboard with one extra row inserted through the center. Same pieces, same rules, same objective, just a little more room to think.
The project is created and directed by Asakura Tetsuo Folco, and built together with Claude, Anthropic's AI — from the core rules engine and AI opponents, to the online multiplayer, to the site you're looking at right now.
What's here today
A full chess engine on the 9-row board, with local two-player play, AI opponents at five difficulty levels, AI vs AI matches, and proper draw handling (threefold repetition, the 50-move rule, insufficient material, stalemate). A move-history "time machine" lets you review any finished game, and Save/Load Game turns any game — finished or not — into a file you can keep or share.
Online multiplayer connects two players directly, with reconnect support if a connection drops, and anyone can watch a public game live from the world map on the homepage — see How to Play for the details.
What's coming
CHESSPLUSONE TELEPATHY — a 2-vs-2 team mode built around coordination without communication. Two teammates share one army, moving in a fixed order, with no chat between them — just the moves on the board to read each other's intentions.
Got an idea?
CHESS PLUS ONE keeps growing based on what makes an interesting game. If you've got feedback or an idea for a new mode, we'd like to hear it — see the Contact page.